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T'. A. EDISON. INGANDESGING ELECTRIC LAMP.

No; 401,646; Patefited Apr. 16, 1889.

INVBNTOR 5 a'omm BY /c@ I WITNESSES:

am 69. (13M.

UNITED STATES 'rnoims noises, oi iinx'nornnni, NEW J :nsnr, AssIoNo TO THE EDISON nrnc' nic Lioirr conPANY, or new YORK, N. Y.

iNCANDES CiNG- ELECTRIC LAMP.

SIPECIFICATION forming part of Letters Patent No. 401,646, dated April 16, 1889.

Application filed August 7, 1882. Serial No. 68,617. (No model.)

To all whom it may concern..-

Be it known that I, THOMAS A. EDISON, of Menlo Park, in the county of Middlesex and State of New Jersey, have invented a new and. useful Improvement in Incandeseing Electric Lamps, ((.ase 3%;) and l do hereby declare that the following is a full and exactdescription of the same, reference being had to the accompanying drawings, and to the let- .ters of reference marked thereon.

I have discovered that in the use of my incandescent electric lamp the stability of the vac- 4min isi'rijured to'some extent by the escape of occludedgases from the metal conductors Within the exhausted glass chamber, which gases cannot practically be entirely driven off when the vacuum is beingproduced, since such conductors are not raised to a high de gree of heat as the carbon lilament is at that time. These occluded gases are not given elf rapidly, but they escape slowly during the use of the lamp, gradually reduing the degree of exhaustion of the lamp. For this reason no means for theabsorption of the gases, applied onlyduring the course oi. manufacturing the lamp or before it is put into com- Inercial use, can be relied upon to overcome completely this dilficulty; but the lamp as commerciallysold and used must be provided with means ever present [or preventing the exuding gases from ail'ecting the condition of the vacuum. I accomplish this objoetby permanently providing lhelamp with a material which will absorb completely the occluded -i use a piece ol elmrwurl, pro

gases as they are given ol'l. Forthis purpose l'e z-ilrly :1. dense cocoanut (ihareoalfivlrieh is'raised to a high degree of heat during the latter part of the process of exhausting the lamp, so as to drive off its own gases. This charcoal must be removed asfar as possible 'fronrthe light, in

order that it may notbe heated thereby in -the use of the lamp, which healing would decrease its capac To do this I inclose the charcoal in a glass tube having a closedoulfcrcnd, and connected at its inner end to the elm-mlnn' ot' the laiup, .at the lower end of such chamber. This tube may be allowed to project directly out .rom the lamp when first attached for cpmvenienee in heating the charcoal by heat from a lamp the lamp.

for absorptionol. gases.

or other source appliedextcrnally to the tube. After the lamp is sealed this tube is heated at its junction with the globe and bent down against the neck of the lamp, it being included in and covered partly or wholly by the molded base, which is afterward formed on by direct radiation from the light, and it dtracted from the symmetrical appearance of During or before the process of exhaustion I may, if desired, place within the globe a compound of chlorine or brominewith any elenm'nt which when heated gii es oif a chlo rino or bromine which will unite with the hydrogen given olf by the carbon filament to form hyd roch lorine or hydrobromine acid gas; or the chlorine or bromine gas may be introduced directly into the globe with the same result. The exhaustion of the lamp is then proceeded with until the highest possible degree of vacuum is attained, when the lamp is Halli-d ull'. ('hzll'cozll. having the POWOI ()f absorbing large quantities of hydrochloricacid or hydrobromic-acid gas without materially impairing-its absorbent capacity for other gases, the modicum of such gases which remain in the globe is taken up by the charcoal in the bulb attached to said globe, and a better vacuum isthus obtained than would occur it air only were left in the globe.

in. lll(5 (ll?l\\'lllf fS, Figure 1 represents the lamp before being exhausted, and Fig. 2'the complete lamp embodying my present inven: tion.

A is the glass globe, B the tubular support oi. glass for the leading-in wires 1 2, and C the incandescing carbon filament.

l) is the tube, containingcharcoal E, which IOO - and the charcoal heated to a high ten1perature, as before-explained, the carbon filament form the knob b, Fig. 2.

connected.

' project from the same, as shown in Fig. 1.

The lamp is exhausted through the tube a,

being also raised to. a high degree of Iincandescence by the passage of an electric current through it. The tube a is sealed off to The tube D is heated and bent down, being covered partly or Wholly by the molded base F, carrying the metal terminals c d, to which the leading-in Wires are What I claim is An exhausted and sealed incandescent electric lamp provided with a tube or vessel containing a gasabsorbing materialsuch as charcoal such tube or vessel being connected with the exhausted chamber of the lamp and embedded in the base of the lamp, substantially as set forth.

This specification signed and witnessed this 10th day of February, 1882.

THOMAS A. EDISON.

\Vitnesses:

Rioni). N. DYER, WM. H. MEADOWCROFT. 

